1. Field of the Invention
The present invention relates to a method of manufacturing a regenerated tobacco material.
2. Description of the Related Art
Various components such as nicotine, nitrates, nitrosamines, hydrocarbons and proteins are contained in tobacco materials such as the leaf, shreds, central vein, stalk, and root of natural tobacco plants. These components are extracted from natural tobacco materials and are used as a flavoring additive to tobacco. These components include those which are desirable to be decreased in amount or to be removed, on one hand, and also include those which are desirable not to be removed or to be increased in amount, in view of the tobacco flavor or some other reasons.
For example, U.S. Pat. No. 4,253,929 and U.S. Pat. No. 4,364,401 disclose a method in which tobacco materials are extracted with an aqueous extracting solvent, followed by subjecting the extracted aqueous solution to an electrodialysis to separate and remove the nitrate ions. Various tobacco articles can be manufactured by adding the extracted solution, having the nitrate ions removed therefrom, to the extraction residue forming fibrous tobacco materials.
U.S. Patent Publication US 2002/0134394 A1 (corresponding to International Publication WO 02/28209 discloses a method in which an extracted solution obtained by extracting tobacco materials with an extracting solvent is treated with a sorption agent capable of adsorbing/absorbing nitrosamines, such as activated carbon, to remove nitrosamines from the extracted solution. Various tobacco articles can be manufactured by adding the extracted solution, having nitrosamine removed therefrom, to the extraction residue forming the fibrous tobacco materials.
International Publication WO 01/65954 discloses extracting nitrosamines by treating tobacco with a supercritical carbon dioxide, and subjecting the extract to a nitrosamine removing process. The nitrosamine removing process includes a separating operation by chromatography. However, this chromatography is not disclosed in detail, and the material to be subjected to the chromatography is not an aqueous extracted material.
In the separating/removing method utilizing the electrodialysis noted above, the object that is to be removed is limited to ions and, thus, the method cannot be used widely. Also, the extracted solution tends to be denatured by the voltage application during the electrodialysis. The extracted solution also tends to be denatured by heating that is applied for improving the separation efficiency. Further, where useful components contained in the dialyzate, having the nitrate ions removed therefrom, is to be used for a certain purpose, it is necessary to apply a concentrating treatment to the dialyzate. A similar concentrating treatment may be required in the separating method using a sorption agent. Also, the method using the supercritical carbon dioxide necessitates a costly apparatus.
Therefore, an object of the present invention is to provide a method of manufacturing a regenerated tobacco material, in which a fraction rich in a desired component and poor in an undesired component and another fraction poor in the desired component and rich in the undesired component are obtained from an extracted solution extracted from natural tobacco materials, and one or both of these fractions are used to manufacture the regenerated tobacco materials.